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With a 2487 or 2489, that's exactly how... No autozero on wavelength changes, equilibrate columnless system w/ 10ug/mL caffeine in water, step through 200-210 and 265-280nm, local maxima should be at 206 and 273 if memory serves.

Also, there is NIST standard grade K2Cr2O7 that can be used to make solutions of well known molar absorbtivities at several wavelengths that can be used, if the caffeine routine lacks sufficient rigor for your taste.